Remove "Create new stream" UI for restricted users.

If a user is not allowed to create new streams, then do not
show the "Create new stream" UI at the top of the settings page.

(imported from commit b97626938d8b612317c2189f7eca0d4bd27fc274)

static/js/subs.js

@@ -420,7 +420,11 @@ exports.setup_page = function () {
         });
 
         $('#subscriptions_table').empty();
-        var rendered = templates.render('subscription_table_body', {subscriptions: sub_rows});
+        var template_data = {
+            can_create_streams: page_params.can_create_streams,
+            subscriptions: sub_rows
+        };
+        var rendered = templates.render('subscription_table_body', template_data);
         $('#subscriptions_table').append(rendered);
 
         _.each(sub_rows, function (row) {

static/templates/subscription_table_body.handlebars

@@ -1,3 +1,4 @@
+{{#if can_create_streams}}
   <div id="create_stream_row">
       <div class="subscription_table_elem">
         <form id="add_new_subscription" class="form-inline" action="">
@@ -8,6 +9,7 @@
         </form>
       </div>
   </div>
+{{/if}}
 
 {{#each subscriptions}}
 {{partial "subscription"}}

zerver/views/__init__.py

@@ -852,6 +852,7 @@ def home(request):
         muted_topics          = register_ret['muted_topics'],
         realm_filters         = register_ret['realm_filters'],
         is_admin              = user_profile.is_admin(),
+        can_create_streams    = user_profile.can_create_streams(),
         notify_for_streams_by_default = notify_for_streams_by_default(user_profile),
         name_changes_disabled = settings.NAME_CHANGES_DISABLED,
         has_mobile_devices    = num_push_devices_for_user(user_profile) > 0,